Thermostat

[the pasty]

Hi.
Looks like my thermostat has gone with the colder weather and have searched through posts looking for info about how easy a job it is to change (2005 2.0 Diesel). Also, read that one might need a software update too?
Pleased if anyone can advise on changing the thermostat and confirm if a software update is also required (and why).
Thank you in advance.

[Guru]

Hi,

What makes you think the thermostat is not working? does the car take ages to warm up?

There are two components in the thermostat body that govern liquid circulation, a classical mechanical valve (no.9 in the diagram) that works by thermal expansion, and an electronic valve called the shut off or "bypass" valve (no.2) that is controlled by the ECM .. the later generates an error code if it's faulty, P2683 to be exact, and as far as I know is a volvo only replacement and it's quite expensive too ..
So better get your codes checked first.

http://666kb.com/i/cvzym4rf32qulbji2.jpg

[the pasty]

Thanks for the reply. Well, I believed it was the thermostat as it does not fully warm up and the heater's temperature output is very low.
However - and I discovered this after my commute this morning - I now have a far more serious issue with oil in the expansion tank. I guess this suggests a blown head gasket!!
From a quick check I could not see any water contamination in the oil - looking at the dipstick and in the top of the engine - but something is seriously wrong. Weird, though, on the journey to work the performance wqas the same as usual - despite oil going round with the coolant. Needless to say, I assume I should not really drive very far (still 35 miles from home) and need to get to a garage asap.
Any thoughts/advice truly appreciated.

[Guru]

Are you sure it's really oil in the coolant tank? can you see a rainbow-like effect floating on the water surface in the tank? or has the coolant just turned to a dark brownish colour?

Could be that the heater matrix is blocked with rust particles and dirt and your coolant system just needs a good flush .. providing the oil isn't contaminated with water too then don't just yet accuse engine sealants and head gaskets.
I'd start off by flushing the coolant system first.

If the oil was contaminated then that still does not mean a blown head gasket .. under the oil filter compartment there is a small rectangular shaped metal box with pipes going in and out of it (red circle) .. that is the oil cooler where engine oil is cooled with water, check that it is not damaged and that there are no leaks at the junctions.

http://666kb.com/i/cw0bp2uarsq9boiuy.jpg

[the pasty]

Many thanks, Guru, for the sound advice. I will check the oil cooler this evening and see how it looks: there is also a fair bit of oil splashed around under the expansion bottle which may suggest another cause. I was not aware there was an oil cooler!
Regarding oil in the expansion bottle, it is definitely oil as it is black and matches the texture/look of the oil on the dipstick :-(
Anyway, will provide an update as I find out more. Appreciate you help.

[msh]

Hi
Please do not shoot me down in flames
There is a test kit that can test if Hydro carbons are present in the coolant. Not sure if it would work with oil in the coolant
Mark

[the pasty]

Update: garage advises the oil cooler has gone.
Given the amount of oil, the garage suggests changing all the affected parts (heater matrix, radiator, pipes, etc.) and of course the oil cooler, as flushing might not clear all the oil: costs going up :-(
Question: is it worth changing all affected parts on a 55plate 143k mile 2.0D?

[cheshired5]

Update: garage advises the oil cooler has gone.
Given the amount of oil, the garage suggests changing all the affected parts (heater matrix, radiator, pipes, etc.) and of course the oil cooler, as flushing might not clear all the oil: costs going up :-(
Question: is it worth changing all affected parts on a 55plate 143k mile 2.0D?

If changing the oil cooler restores coolant/oil separation, I'd keep my money in my pocket and go for a radiator flush instead to clean any other contaminated pipework, then see how things are.

[Guru]

Just flush throughly using a good radiator flush fluid .. It will be a tedious job but worth it considering how difficult it is to reach the heater matrix on these cars ..

But the radiator is fairly easy to remove .. You can take it out, flush it with petrol or naphtha then remount it.

Oli remnants in the cooling system will eventually gather up in the expansion tank and float on the surface .. You'll be sipping them out from there on the long run.

How much for an oil cooler on these cars? Nothing lasts for ever but I don't think it should have gone as it's not a wear and tear item .. Have you maintained a regular oil filter change ?

[the pasty]

We'll go down the multi-flush route and shall likely remove the radiator too to ease cleaning, hopefully over this weekend. Oil/filter changes have been regular. Will provide an update on outcome.
Thanks.

[the pasty]

Managed to fit the newer (2nd hand) oil cooler last weekend and flush through the coolant system, having removed the radiator for a thorough flush: flushed system 6/7 times before the contents looked clear, then refilled with recommended coolant mix. Test drove Saturday/Sunday and minimal oil deposits in expansion bottle.
Continued with daily commute (70 miles) for 4 days last week and have just seen small amounts of oil collecting in the expansion bottle: more importantly though, no sign of the oil level dropping or engine oil being contaminated with water, so hopefully have diagnosed and resolved the problem: will no doubt be removing oil deposits from the expansion bottle for a while, though, as it slowly flushes around.
Will post an update if anything else untoward happens, but thank you for your advice/comments.

[the pasty]

Final update (one hopes). No error codes, so proceeded with thermostat change. Haynes manual said it was simple (1 spanner), but it was somewhat more complicated (further details available on request).
After several hours, managed to remove the hoses and old thermostat to find the rubber gasket on the wax stat had split, meaning coolant had been circulating all the time. Anyway, put all back together again and now get heat from the heater!!
Thank you all for your help/opinions.:thumbs_up:

[Ben83]

Hi I am new to the volvo oners all together I have just bought a 2005 s40 2.0d and I have water leaking from that area would water leak out of the oil cooler as soon as you pour it in cheers Ben83